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Science : Fossil birds fly in the face of theories

TWO recent discoveries of ancient bird skeletons in Spain and Madagascar have
forced palaeontologists to rethink their theories about the diversity of
birdlife in the age of the dinosaurs.

The beautifully preserved bones of Vorona berivotrensis, a new and
very primitive species unearthed in northwestern Madagascar, is the first
specimen from the Mesozoic era, 65 to 245 million years ago, to be found in a
large portion of the ancient continent of Gondwana, the part that is now Africa,
India and Antarctica. It is also the first pre-Holocene—older than 10 000
years—bird found in Madagascar.

The Spanish fossil, Eoalulavis hoyasi, showed that birds had evolved
their efficient, modern style of flight as early as 115 million years ago. “The
diversity of early birds was much larger than we thought five years ago,” says
Luis Chiappe of the American Museum of Natural History, New York.

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The lower limb of the Madagascan bird, which was about the size of a crow,
indicates that it was closely related to the most common group of dinosaur-age
birds, the extinct Enantiornithes. The find is reported in this week’s
Nature (vol 382, p 532).

The Spanish find was about the size of a goldfinch. It had a well-preserved
wing with many feathers in their original positions, and shows a crucial stage
in the evolution of flight. E. hoyasi lived only about 30 million years
after the first bird, Archaeopteryx, but had already evolved the
“bastard wing” that allows modern birds to manoeuvre among trees. “It would have
flown like modern birds,” says Chiappe, who co-authored a paper describing it in
last week’s Nature (vol 382, p 442).